Pumps are used in a variety of settings for moving liquid matter through a type of conduit made to contain the liquid (or gas). Some types of pumps have evolved into devices used in environments that require high precision and long mission times. For example, turbomolecular pumps are used to create a vacuum in a chamber. Turbomolecular pumps typically operate at high rotational speeds and may be required to operate for long periods of time in which it may move isolated molecules out of the vacuum chamber. Typically, turbomolecular pumps move the gaseous matter from the chamber into a conduit having a backing pump to assist in moving the matter completely out of the chamber. Once the vacuum forms, the pump may be required to remain on in a vacuum state to maintain the vacuum.
Like any other device, turbomolecular pumps will fail after some time in operation. The failure of a turbomolecular pump can be costly. Replacement of the pump requires a shutdown of the application in which it was operating. Where the application involves a production line, the shutdown means delays in production and reduction in volume. The failure may also cause a loss of products that would need to be disposed of if the loss of vacuum spoils the product. Similar scenarios involving added costs and inefficiencies may be present in other types of applications.
Turbomolecular pumps are currently tested for long-term lifetime ratings during the design and manufacture of the pumps. These tests however involve large sample sizes and may require long periods of time, up to a year or more, to obtain statistically significant sample sizes delaying entry into the market and adding cost to both development and manufacture. Despite all of the testing, it is still impossible to determine when any one individual pump will fail.
In view of the foregoing, there is an ongoing need for pump testing methods that predict pump failures and lifetime.